Backups in sharded clusters

For PBM v1.0 (only)

Before running pbm backup on a cluster, stop the balancer.

In sharded clusters, one of the pbm-agent processes for every shard and the config server replica set writes backup snapshots into the remote backup storage directly. For logical backups, pbm-agents also write oplog slices. To learn more about oplog slicing, see Point-in-Time Recovery.

The mongos nodes are not involved in the backup process.

The following diagram illustrates the backup flow.

Important

If you reshard a collection in MongoDB 5.0 and higher versions or unshard a collection in MongoDB 8.0 and higher versions, make a fresh backup to prevent data inconsistency and restore failure.

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Last update: February 20, 2025
Created: February 20, 2025